django reverse causes circular import

Question

I have this in my project urlconf photocheck.urls:

urlpatterns = patterns('',      url(r'^admin/docs/', include('django.contrib.admindocs.urls')),     url(r'^admin/', include(admin.site.urls)),     url(r'^rest/', include('core.urls')),     url(r'^shotmaker/', include('shotmaker.urls')),     url(r'^report/', include('report.urls')),     url(r'^users/', include('users.urls')),  ) + static(settings.MEDIA_URL, document_root=settings.MEDIA_ROOT) 

this is my core app urlconf:

router.register(r'cameras', views.CameraViewSet) router.register(r'lamps', views.LampViewSet) router.register(r'snapshots', views.SnapshotViewSet)  urlpatterns = patterns(     'core.views',     url(r'', include(router.urls)) ) 

this is shotmaker urlconf:

urlpatterns = patterns(     'shotmaker.views',      url(r'^$', views.CameraList.as_view(), name='camera_list'),     url(r'^camera/(?P<pk>[-\w]+)/$', views.CameraDetail.as_view(), name='camera_detail'),     url(r'^save_preview_image/(?P<pk>[-\w]+)/$', views.save_preview_image),     url(r'^get_position/(?P<pk>[-\w]+)/$', views.get_position),     url(r'^set_position/(?P<pk>[-\w]+)/$', views.set_position),     url(r'^update_calibrating_image/(?P<pk>[-\w]+)/$', views.update_calibrating_image),     url(r'^save_preview_get_position/(?P<pk>[-\w]+)/$', views.save_preview_get_position),   ) 

and report urlconf

urlpatterns = patterns(     'report.views',     url(r'^$', views.LampReportView.as_view(), name='lamp_report'), ) 

and users urlconf

urlpatterns = patterns('', url(r'^login/$', views.MyLoginView.as_view(), name="login"), url(r'^logout/$', LogoutView.as_view(), name="logout"), ) 

now when I do

reverse('lamp_report') 

i get this:

Traceback (most recent call last):       File "<console>", line 1, in <module>       File "/Users/1111/.virtualenvs/gost_photo/lib/python2.7/site-packages/django/core/urlresolvers.py", line 546, in reverse         return iri_to_uri(resolver._reverse_with_prefix(view, prefix, *args, **kwargs))       File "/Users/1111/.virtualenvs/gost_photo/lib/python2.7/site-packages/django/core/urlresolvers.py", line 410, in _reverse_with_prefix         self._populate()       File "/Users/1111/.virtualenvs/gost_photo/lib/python2.7/site-packages/django/core/urlresolvers.py", line 269, in _populate         for pattern in reversed(self.url_patterns):       File "/Users/1111/.virtualenvs/gost_photo/lib/python2.7/site-packages/django/core/urlresolvers.py", line 367, in url_patterns         patterns = getattr(self.urlconf_module, "urlpatterns", self.urlconf_module)       File "/Users/1111/.virtualenvs/gost_photo/lib/python2.7/site-packages/django/core/urlresolvers.py", line 361, in urlconf_module         self._urlconf_module = import_module(self.urlconf_name)       File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/importlib/__init__.py", line 37, in import_module         __import__(name)       File "/Users/1111/_gost/photo/photo-monitoring/photocheck/urls.py", line 15, in <module>         url(r'^users/', include('users.urls')),       File "/Users/1111/.virtualenvs/gost_photo/lib/python2.7/site-packages/django/conf/urls/__init__.py", line 28, in include         urlconf_module = import_module(urlconf_module)       File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/importlib/__init__.py", line 37, in import_module         __import__(name)       File "/Users/1111/_gost/photo/photo-monitoring/users/urls.py", line 4, in <module>         import views       File "/Users/1111/_gost/photo/photo-monitoring/users/views.py", line 6, in <module>         class MyLoginView(LoginView):       File "/Users/1111/_gost/photo/photo-monitoring/users/views.py", line 8, in MyLoginView         success_url = reverse('lamp_report')       File "/Users/1111/.virtualenvs/gost_photo/lib/python2.7/site-packages/django/core/urlresolvers.py", line 546, in reverse         return iri_to_uri(resolver._reverse_with_prefix(view, prefix, *args, **kwargs))       File "/Users/1111/.virtualenvs/gost_photo/lib/python2.7/site-packages/django/core/urlresolvers.py", line 410, in _reverse_with_prefix         self._populate()       File "/Users/1111/.virtualenvs/gost_photo/lib/python2.7/site-packages/django/core/urlresolvers.py", line 269, in _populate         for pattern in reversed(self.url_patterns):       File "/Users/1111/.virtualenvs/gost_photo/lib/python2.7/site-packages/django/core/urlresolvers.py", line 376, in url_patterns         raise ImproperlyConfigured(msg.format(name=self.urlconf_name))     ImproperlyConfigured: The included urlconf 'photocheck.urls' does not appear to have any patterns in it. If you see valid patterns in the file then the issue is probably caused by a circular import. 

so where is the circular import here? and how can I avoid it?

Answer 1

Use reverse_lazy() instead of reverse().